Tire-casing.



J F. PALMER.

TIRE GASING. APPLICATION FILED- 00'1.12,1906.

' Patented June 8,1909.

2 SHEETS-SHEET 1.

J. P. PALMER.

TIRE CASING.

APPLICATION FILED 0o'r.12, 1905.

924,57 1. Patented June a, 1909.

2 SHEETS-{REST 2.

hnior.

UNITED srA'rEs PATENT oFFIo JOHN F. PALMER, or CHICAGO, ILLINOIS.

TIRE-CSING.

Specification of Letters Patent.

Patented June 8, 1909.

Application filed October 12, 1905. Serial No. 282,373.

.which is open on the inner or rim side to 'receive an inner tube, andwhich can be bodily removed from the rim when desired. In other words,the improvements are in the type of tire, commonly known as thedetachable tire.

The object of my invention is to provide for such tires an outer casinghaving certain desirable qualities hereinafter set forth, and

which can be constructed at a comparatively low cost and. in a simplemanner.

; My invention can be embodied in tires,

' or more properly tire casings, of various forms of which I haveillustrated two in the drawings. It will be noted, however, from thefollowing description and explanation that other modifications can bemade and it will, therefore, be understood that by illustrating thesetwo forms I do not intend to limit myself thereto.

In the drawings referred to, Figure 1 is a side elevation of one form ofmy improved casing, a portion of the outercovering of rubber beingremoved to show the winding of the band forming the strengthening element thereof; Fig. 2 is a transverse section through the completed tirein the line 22 of Fig. 1; Fig. 3- is a transverse section through themandrel which I prefer to use for forming the tire; Fig. 4 is adiagrammatic view showing the winding in detail; Fig. 5 is a similardiagrammatic view showing a second form of the casing, and Fig. 6 adetailed view on an enlarged scale showing the joining together of twoparts of the band.

Referring to the drawings, A, is an annular .mandrel, arch-shaped incross-section and provided at its inner edge with laterally extendingflanges, a. To permit this mandrel to be readily removed from theannular casing formed thereon the mandrel is made of three sections, A AA the sections A and'A beinghinged to the section,- A and being arrangedto meet in a diagonal, line and be joined together. It -will be obvious, by reference to Fig. 4 of the drawings, that when the complete tirecasing is formed on the mandrel the mandrel can be readily removed bydisconnecting the segments, A and A, and folding the mandrel inward.

In the formation of my improved tire casing, the mandrel is expanded toform a complete annulus and its parts are locked together, as shown inFig. 4, and usually covered with a thin layerof some very elastic wovenor knitted fabric, B, such as stockinet,

frictioned on the outer side, although this layer may be omitted ifdesired. After this layer has been placed upon the mandrel, I wind overit a plurality of circumferential turns of a comparatlvely non-elasticband,

which, preferably, is first suitably rubbercovered to make it adherent.The method of winding this band will be best understood by referring toFig. 4, where it will be seen that the first strand, 0, of the bandstarts at a point, '0, on the tread ofthe casing; that from thepoint,'c, it extends to a point, a, on

the inner or free edge of the casing which it strikes at a tangent; andthat it extends thence, following as far as possible the same straightline to a second point, 0 on the tread of the casing. In this way thisstrand, C, forms a chord of an arc, when. viewed in side elevation, thechord being tangent to the circle of the free edge of the casing at itspoint of contact therewith and being in a plane at right angles to theface of the casing. The band, when it reaches the tread at 0 is laidacross the tread and from thence is carried forward to form the secondstrand, C, which is on the opposite side of the casing from the firststrand and runs in a similar manner, 11. e. in a straight line from thepoint, 0 to the point, 0 on the tread of the casing and tangent at thepoint, 0 to the inner or free edge thereof. The band, when it againreaches the tread of the casing at c, is brought back across the treadto form the third strand, G which is on the same side of the casing asthe strand, 0, and extends from the point, a, to the point, 0 beingtangent to the curve of the free edge at 0 When the band reaches thetread of the casing at 0,

which, like the strand, C is on the rear side of the casing, as viewedin Fig. 4. This strand-follows a course similar to that of the strand,C, and after passing the free edge of the'casing on atangent line, at 0,reaches the tread of the tire at c slightly in advance of'i'the point ofdeparture, c, of the first strand, 0. The band is then laid across thetread to form a fifth strand, Cf, which lies in advance of the firststrand, C, and crosses it very near its point of tangency to the freeedge of the casing. The wrapping of the band is continued in the sameway to form other strands, each one of which lies in advance of thecorresponding strand immediately preceding it. It will be seen that byfollowing this course of winding the entire surface of the inner layer,B, may be covered with a layer of strands, each one of which runs inopposite directions from a point on the free or inner edge f the casingto two points on the tread. It willbe evident that the band may crossthe treadof the casing more or less than four times in making a completecircuit thereof. The number of crossing points in a single circuitobviously depends upon the ratio between the cross-sectional diameter ofthe tire and the diameter of the wheel. Where the tire is comparativelysmall, like a bicycle tire, there are a number of crossing points, andas the crosssectional diameter of the tire is increased in proportion tothe diameter of the wheel the arcs subtended bythe strands becomegreater and consequently the number of crossing points in a singlecircuit decreases. When it is wound continuously about the circumferenceof the casing (as illustrated in the drawings) the arcs subtended by thestrands of each circuit should be such that in the winding of thesuccessive circuits the crossing-points will be distributed in suitablesuccession about the circumference instead of lying one directly overthe other. Obviously, however, each complete circuit might be formedfrom a short band or a plurality of short bands having their ends lappedor otherwise secured together as indicated in Fig. 6, in which referencecharacters C and 0' indicate the overlapped portions of two bandssecured together to .form a continuous band, and in that case, thespaces between the crossing-points should preferably be such as to forma complete and exact circuit ending at its starting point. In buildingtires,

the windingl1 thus explained can be continued inde itely, one completelayer being wound over another until the requisite weight and strengthare produced. For instance, the tire shown in Fig. 2 has two layers ofstrands on the tread; and this number may be increased as required.After the winding is completed, the usual outer protective layer ofrubber may be placed in position. This can be done either before orafter the casing is vulcanized. 1

It will be seen that as the band is carried about one complete circuitof the annular casing (as in forming the strands, C, C, C C) it crossesthe tread of the casing at a series 01 points (as the points, 0, 0*, c,c, c);

. that it anchors together each two successive crossing-points (as theoints, cc, c 0, 0 -0, c-c*) and that 1t also anchors each crossing-pointon the tread to two tangentpoints on the inner or freeedge of thecasing, each crossing-point in. the tread being anchored to the twotangent-points between which it lies. point, 0', is anchored by thestrands, C, C, to the tangent-points, 0, c and each of the tread-pointsis similarly anchored by the corresponding strands to two tangent-pointson the inner or free edge of the casing. Furthermore, while any giventread-point is an chored by the strands of one layer to twotangent-points lying on opposite sides of it (and on oppositesides orfaces of the casing), the same tread-point is anchored by the strands ofthe next superposed layer to two other tangent-points on the free edgesof the casing, and these points he directly opposite the tangent-pointsto which the same tread-point is anchored by the strands of the firstlayer. That is to say, each tread-point is anchored by the strands oftwo successive layers to four tangent-points on the inner or free edgesof the casing; and two of these tangentpoints lie on one side or face ofthe casing and the other two on theother side or face thereof, thetread-point being at a center between the four tangentepoints to whichit is so anchored. The successive points on the tread being thusanchored together, the casing may be described as self-contained inpoint of resistance to radial strain; and since in ractice each freeedge of the casing is held immovably to the rim of the wheel, each pointon the tread may be said to be anchored to four points on the wheel rim,the lines of connection running tangentially from said rim so as totransmit power to the tread in a theoretically perfect manner. In actualpractice, the tire will fall short of perfect transmission only bythe'amount of elasticity inherent in the band and the amount ofstraightening of the band under stress due to the lateral curvature ofthe line it describes across the tread. of the tire. It is, therefore,obviously desirable that the band be of some comparativelynon-extensible material, as, for instance, linen, cotton, metal, or thelike. If, however, any more elastic band is used, the invention will beequally present, although the actual embodiment will be less effective,for whatever be the character of the band, it obtains its greatestefficiency when arranged as here illustrated.

If the band be of fabric, such fabric may be of any desired sort, butpreferably has no cross-threads, but only longitudinal ones, forcross-threads put kinks in the longitudinalthreads, and so give them thepossibility of Thus, for instance, the tread-' edges.

longitudinal stretch. \Vhile I prefer" a fabric .havingonlylongitudinalthreads, I do'not intend to limit myself thereto for myinvention consists rather in the arrangement of the band than in itsphysical characteristics. A woven fabric is undesirable in a tire,whatever it-s arrangement, by reason of the kinks in the threads and theresulting stretch and friction of the-threads; but it will transmitpower more effectively when wound. as illustrated than in anyrotherarrangement within my knowledge.

It will be seen that along the inner or free edges of the casing, thestrands of the strengthening band are piled one upon the other so thatthe maximum thickness of the casing is along these edges. It will alsobe seen that as the width of the band is decreased, the number of turnsnecessary to cover the tread completely with agiven number of layerswill be increased, with a consequent increase of the number of layers onthe inner or free ed es of the casing. If the band is too muc decreasedin width, the number of layers on the free edges will become extremelygreat, causing a large and unnecessary increase ofmaterial along theseThis accumulation of material on the extreme inner edges can becontrolled by winding the band as illustrated in Fig. 5, where a widerband is used than is shown in Fig. 4, and each strand is lapped on thenext preceding one on the tread to an amount equal, in the formillustrated, ,to half the widthof the band. As an illustration of theeffect of such winding upon the inner edge of the tire, let us assumethat a band an inch wide wound as in Fig. 4 with the strands just.

touching each other on the tfeadwould produce an inner edge one-half aninch thick. The free edges would then be one-half an inch thick, for theinside inch, and would then gradually taper off to the tread. If nowinstead of this band, a band two inches wide be used, and each strand belapped half over the preceding one on the tread, as seen in Fig. 5, thenthe same amount of strainresisting material will be incor orated in thetire with half the number 0 strands, but each strand will be twice thewidth required in the otherform. As a result, the extreme inner edgewill be but a quarter of an inch thick, but the inner two inches willhave this thickness before beginning to taper off, instead of the innerinch. It will be seen that by following this method of lapping the bandsand increasing their widtr roportionately the strain-resisting materiacan be spread through the side walls of the tire to any desired extent,thus preventing at will any undesirable accumulation of material alongthe inner or free edges.

cs tudinal strands only is interchangeable in most positions with aseries of parallel threads laid simultaneously so that wheninc'o'rporated in the tire, they form, ractically speaking; a singleband and by t e use of the term band in the s ecification and in theclaims hereto appen ed I intend to cover any ta e-like memberof-anymaterial or any I co lection of filaments of any material pro-.

vi ded they are laid upon the tire side-by-side,

so as to produce the same effect as if a unitary band had been laid. I

If, as in the preferredform of construction, the fabric band is composedof a plurality of longitudinal threads held together only by the rubberof the band, it will be seen that the use of the band furnishes aeouliarly convenient means for distributing t e strainresisting threadsor filaments of the band through theside walls of the casing. Othermeans for distributing the strain-resisting threads or filaments in asimilar manner can readily be devised. One of the most importantfeatures of m present invention resides in the fact that t e threads orfilaments are distributed through a redetermined annular area at theinside er ges of the casing, the threads orfilaments of each strand ofthe band being tangent res ectively to a series of circles outside of,an concentric with the inner edges of the casing, so as to procure themaximum strengthening and power-transmitting efi'ect without an undueaccumulation of material along the inner edges. A tire wound in the samegeneral manner as that shown herein, but 'With thestrands of thestrengthening threads all running to the exact inner or free edges ofthe tire might be advantageous in some respects, but the inner edgeswould be so thick as to make the tire unwieldy (and comparativelyimpractical). In my tire the inner edges can be made of any desiredthickness and the strengthening material can be distributed as desiredthrough the side walls.

It will be evident to anyone skilled in the art of tire constructionthat when a flat band is wound upon a mandrel having a circular orpartially circular cross-section, as herein illustrated, the bandnecessarily varies slightly from a single plane as it crosses the curvedportion of the tire. For the sake of greater clearness, I haveillustrated the tire in the drawings without this slight curvature and Ihave spoken in the claims of the bands as lying in a single plane. Bythis language I mean merely that they shall lie substantially in thesame plane,'it being understood that each strand will be laid to followthe curvature of the mandrel and its variation- &

.be quite a variation from a single plane.

lateral curve each portion of the winding connecting two tread ointsfollows the shortest possible ath a ong the surface of the tire and the'stance between any two tread points can be increased only by causing agreater compression of the contents of the tire.

The advantages of my tire have been set forth to a considerable extent.in describing 'its construction. Briefly, the structure is such thatextremely efiicient transmission of powerbetween the rim of the wheeland the tire tread is obtained by reason of the strands lying at adirect tangent from each rigid point of the rim to the corres endingpoints on the tread of the tire. urthermore, it secures great ease oftransverse and lateral movement of the filament-strands and consequentmaximum cushioning quality and resiliency v It wil be seen that sincethe band can be wound upon the tire with mathematical accuracy, thestructure lends itself particu-' larly to automatic machine manufacture,and thus minimizes the ever-present danger of defects due to carelessand ineflicient hand-labor.

In the foregoing description of my improved tire-casing and in theclaims appended hereto, I have described the bands as tangent .to thefree edges of the casing. In fact, the bands are tangent to circlesparallel to the free edges of the casing; and these circles arereferably so near said edges as to be practica ly coincident therewith,as shown in the drawings. The distance between these circles oftangency, and the extreme inner or free edges of the casing might besomewhat varied as compared with the illustrated constructions; and theconstruction would still be Within the intended meaning of thedescription in question.

I claim as new and desire to secure by Letters Patentr 1. A tire casingopen on the rim side and containing a. strain-resisting band woundcircumferentially about the casing for at least one turn and crossingthe tread thereof at intervals, said band touching at a tangent theinner or free edges of the casing in the intervals between its crossingpoints on the tread.

' 2. A tire casing open on the rim side and containing astrain-resisting band com osed of a plurality of parallel strands, one ege of the band being arranged at a tangent to one of the inner or freeedges of the casing and extending thence across the tread where theoppositeedge of the band is tangent to the inner or free edge on thatside of the casing.

3. A tire casing open on the rim side and embodying a strain-resistingband tangentially disposed to the free edges thereof.

4. A tire casing open on the rim side and embodying a plurality of turnsof a strainresisting band which crosses the tread at intervals and.touches the inner or free edges of the casing at a tangent between itscrossing points on the tread, the crossing points being so disposed thatthe succeeding turns of the band are la )ped upon each other on thetread whereby the thickness of the inner edges is decreased as comparedwith the thickness of the tread.

5. A tire casing open on the rim side and embodying a series ofsubstantially parallel strain-resisting filaments, the strands of whichconnect separate tread points, the central portions of saidfilament-strands intermediate of the connected tread points beingdistributed according to a pre-arranged scheme throughout apredetermined annular space along the inner or free edges of the casing.

6. A tire casing open on the rim side and embodying a plurality ofstrands of strainresisting filament which connect separate tread points,said strands being tangent intermediate of the connected tread points toa series of circles concentric with the edges of the tire casing anddistributed throughout a predetermined annular band.

In witness whereof I have signed the above application for Letters Patenat Chicago, in the county of Cook and State of Illinois, this 10th dayof October, A. D. 1905.

JOHN F. PALMER.

VV'tnesses:

CHAs. O. SHERVEY, K. M. CORNWALL.

